Control mechanism for hydraulic systems of rotary drilling rigs



May 12, 1953 R. R. CROOKSTON CONTROL MECHANISM FOR HYDRAULIC SYSTEMS OF ROTARY DRILLING RIGS Filed Nov. 29, 1950 POSITIONING MOTOR 3 Sheets-Sheet l AIR SUPPLY 2 PHASE MOTOR AIR SUPPLY 92 ADJU .6 POWER SOURCE 9O :[1% AIR SUPPLY STABLE VOLUME i ll' HYDRAULIC fSYSTEM INVENTOR.

Robert R. Crooksfon A TTORNE Y.

y 2, 1953 R. R. CROOKSTON 2,638,319

CONTROL MECHANISM FOR HYDRAULIC SYSTEMS OF ROTARY DRILLING RIGS I Filed Nov. 29, 1950 5 Sheets-Sheet 2 Imn IIIIIIIIIIIIIII INVENTOR. Robert R. Crookston,

ATTORNEY.

y 1953 R. R. CROOKSTON 2,633,319

CONTROL MECHANISM FOR HYDRAULIC SYSTEMS OF ROTARY DRILLING RIGS Filed Nov. 29, 1950 s Sheets-Sheet 5 BEARING ROLLERS INVENTOR. Robert R. Crooksfon Maw W qrronuzv.

Patented May 12, 1953 GONTRO-L 'MECHANISM FOR -HYDRAULIC SYSTEMS OF ROTARY -DRILLING RIGS Robert E. Crookston; Houston, Tex., assignor, by

meme assignments, to Standard flit Development; Company, Elizabeth; N. .J., a corporation of lie'laware .Application'November 29, 1950,.Serial bio/198,189

3 Claims. I.

This application is directed to acontrol mechanism for ahydraulically controlled system for drilling oil wells of the "type disclosed in U. S. Patents 1,831,437, 'Brantly, November 10,1931; 133,016, 'Brant'ly, October 11, 193-8; and 2,489,449, Crookston, 'Novembert29, .1949.

"More specifically, the device of the present invention is a control. mechanismt'o be used on a rotary drilling rig which is provided'with a hydraulic system controlling the rate of feed-oil andhaving a weight indicator for the'drill bit which is capable of producing an electrical signal. The control mechanism ofthepresent invention is arranged to be :activated by electrical signals from theweight indicator and when so activated alters the "rate of how through the hydraulic system in response to" said electrical signals. Other objects and advantages of the present invention will'be seen from the following description takenin 'conjunctionwith' the drawing in which:

Fig. 1 is in the "form of a diagrammatic flow 'sheet' showing a preferred "embodiment of the system of the present invention;

Fig. 2 is an elevatiompartly in section, showing details ofconstruction "of a suitable compressed air valve'shown schematically in Fig. 1;

Fig. 3 is a 'viewtaken along line IIl.'-'---EIIof "Fig; I 4 *is' a schematic showing of the relationship between parts of a rotary-drilling rig and a" weight indicator assembly, parts ofwhich :are

shown "in Fig. '1.

Turning' now specifically ate the drawing and 'firs'tto'Fig. 1,-a suitable unitdorproducing -elec- 'trlcal signals. in response to changes: in: the-weight ca'rried' by the drillbit" is designated bythe part enclosed within dashed .lines and identified-shy I. SI-he' valve mechanism activated in response vided with suitable valves which I is designated as III. It will be understood .thatlthe structure identified by III-may be part of-a 'complete'hydraulic system such as describedinU. S. Patents 1,8311437, 2133,016, and 2,489,449.

In Fig. .1 the receiving unit of "the weight indicator assembly IV is shown. "The weight indicator assembly IV is shown schematically in Fig. 4 in relationship to the parts of the conventional hoisting apparatus for rotary drill- In Fig; 4 drawworks N is provided with drilling line 2. By means of a derrick and crown block (which'have been omitted from the drawing in order to simplify it) the drilling line suspends the travelling block 3, swivel 4 and kelly 5 which passesthroug-h rotary 6, the lower end of the k'elly being attached to the drilling pipe which is not shown since it is in the borehole. The weight indicator assembly IV'consists of weight responsive element 1 arranged in the swivel and connected through electrical lead 8*to receiving unit C.

Turning now specifically to Fig. 1 and to that portion of the assembly designated by I, a split shaft [8 which is the shaft of receiving unit C of weight indicator assembly IV and moves angularly in responseto variations in the weight carried by the-drill bit. Since such weight indicators are known to the art, the details of constructionare not shown. The primary H! of transformer Bis connected through leads '20 and 2! to asuitable source of alternating current '22.

Changes in the output of potentiometer A are "transmitted to two-phase positioning motor D ofII. One of the field coils 23 of motor D is connected through lead 24' to the center tap 25 of-"a secondary ll of transformer B and through lead lll'to contact! of potentiometer A. The other "field coil 26 of motor D is connected through conductors 21 and 2! to alternating current supply 22 and through conductor 23 to one plate of condenserZQ. The other plate of condenser 29tis connected through make and break switch 30and conductors 3! and 2!! to alternating current supply '22. A two-phase motor E is coupled through shaftSZ to interrupter cam 33 arranged to activate make and break 'switch'sll. Two-phasemotor E is connected to .the source of alternating current 22 by con- '-ductors '34 and 2s and 35 and 21.

The purpose of the arrangement of two-phase motors D-and E" in conjunction withthe weight indicatorC is to insure that the bias exerted by motor D is instantly responsive to changes in "the positionof potentiometer slide M. By the-use of interrupter switch 3!] which is continuouslyinterrupted by interrupter cam 33; the effect of hysteresis in two-phase motor D is =la'rge1y overcome.

longitudinal movement along the cylindrical wall I 4| of the wall body is of generally cylindrical shape provided with circumferentially extending groove 49 at its center portion which is connected through radially extending port 59 and longitudinally extending port i with the end 52 of the piston. The other end 53 of the piston is connected through rod 54 and mechanical linkage G to two-phase motor D.

Two-phase motor D' drives shaft 550. Mounted on shaft 60 are gears s1 and 62. Gear 62 is arranged to mesh with toothed quadrant 63 which is mounted on shaft 64 and has secured thereto a downwardly extending lever arm 65 which is connected through pivoted arm 66 to piston rod 54. Shaft '69 is biased to a predetermined normal position by means of a rack .tact with the frame m of assembly G and its other end in contact with a head 68.

Thus when two-phase motor D rotates shaft 60 and forces rack 5'! from its normal position a bias is exerted on the rack to return it to the normal position. The continual interruption of the current to motor D caused by the activation of switch 30 substantially eliminates the effect of hysteresis in the two-phase motor D and allows a substantially instant response in changes in the current resulting from changes in the position of potentiometer A. Rotation of motor D causes movement of piston 42 in cylinder 40 through the linkage described.

The hydraulic assembly III consists of oneway valves Ill, II, (2, and I3, valves I4 and I5 which are controlled by air pressure and a needle valve 16 which is also controlled by air pressure. Branched line TI connects to the inlet of one-way valve It and to the outlet of one-way valve 12. Branched line I8 connects to the inlet of one-way valve H and to the outlet of one-way valve 12. Line 19 connects the two outlets of one-way valves I0 and TI. Line 80 connects the inlets of valves I2 and 13. Line 8| with valves I4 and I6 arranged therein connects lines 79 and 80. Line 82 with valve I5 arranged therein connects lines 19 and 83.

Pump M is mechanically connected to drawworks N. Hydraulically, one side of the pump is connected to line I1 and the other side to line 18. It will be understood that one of the lines is connected to the inlet of pump M and the other line to the outlet of pump M but in the manifold shown it is immaterial which side is the inlet and which side is the outlet and for that reason they are not specifically designated. Pump M is shown schematically in the drawing since specific details of construction of suitable pumps are shown in my Patent 2,489,449 and in the Brantly Patents 1,831,437 and 2,133,016, heretofore mentioned.

The activating mechanism of valve I4 is connected by compressed air line 85 to port 43 of valve F and the activating mechanism of valve is connected by compressed air line 84 to port 46 of valve F. Air is supplied to line 83 from a 4 suitable source of compressed air, not shown, connected by inlet line 85 containing orifice 86. To allow an adjustment of the speed of operation of valve I4, an adjustable volume 8! is connected to line 83 through branch 88.

Line 84 is connected to a suitable source of air supply, not shown, through line 89 containing orifice 90. In order to allow adjustment in the speed of operation of valve 15 adjustable volume BI is connected to line 84 through branch 92.

Needle valve I6 in the hydraulic system 111 is provided with a rotatable stem 93 on which is mounted a toothed wheel 94 which is rotated by a mechanism which is in eifect a pair of air motors with their operation controlled by valve F. A cylinder and piston assembly H is arranged to rotate toothed wheel 96 in a clockwise direction and a cylinder and piston assembly J is arranged to rotate toothed wheel 94 in a counterclockwise direction. Each of the assemblies H .and J consists of a cylinder 1%, a piston llll,

piston rod I02 connected to the piston, a ratchet member I03 pivoted to the end of the piston rod and arranged in engagement with toothed wheel 94 and a spring I04 is arranged to bias the piston IE3! toward the head end of cylinder we. Piston and cylinder assembly H is connected by line I85 to a compressed air assembly K and assembly J is connected through line IIJG to assembly L. Assemblies K and L are identical to each other. Each has a line I01 which contains an orifice I88 and is connected to an air supply line Hi9 and to the inlet of interrupter valve III]. The outlet of the interrupted valve of assembly K is connected through line llIto port 44 of valve F and the outlet of the interrupted valve of assembly L is connected through line H2 to port 45 of valve F. Connected to line IiI'I of each assembly K and L is a manifold consisting of line H3 containing one-way valve H4 and orifices H5 and line H6 containing orifice III. Orifices I I5 and I I1 are connected through branched line H8 to the activating mechanism of interrupter valve H0 and to variable volume H9.

The operation of assemblies K and H is in effect an air motor which operates only when its exhaust is allowed to discharge to the atmosphere. When the device is allowed to discharge to the atmosphere the cycle is as follows: Air from air supply line I09 passes through orifice I08 into cylinder I00 of assembly H and through orifice III into volume H9 and to'the activating portion of interrupter valve H0. The pressure eventually builds up to a value in the operating portion of interrupter Illl sufficient to cause this valve to open whereupon air discharges through line I I I, air being withdrawn from cylinder I00 as well as from volume H9. The oneway valve I I4 insures that the air is quickly discharged from the operating portion of valve H0 as well as from cylinder Hill. The discharge of the air in this manner causes piston Iii! to move upwardly and to turn the toothed wheel 94 through an arc in the clockwise direction. After a fixed interval of time interrupter valve III closes allowing the air from air supply line I89 and bleeding through orifice I08 to fill cylinder I00, thus forcing piston Illl downwardly and gradually filling the operating portion of valve I II) until the predetermined pressure for activating valve III! is again reached, whereupon the valve discharges and the cycle is repeated.

The combination of assemblies J and L operates in exactly the same manner as the assem- MWIQ except assemhi yurotates todthe'd he c'ountercieciiwi er direction zrr heexhaustrrom:assembries n andrmhrough line it: iscontr'o11ed by itnev pcsi tion or valved. like exhaust from assemblies; through medley-valve F. M i rating it are raster-rate tn nearrpassfrom the air supply This" s council-es ay va'ive F, siiiiiiarly, valve re is activated hy ex"- nausnng *tlireugnsline s 4 at" a raster rate: than ean ipass from trie airsnppiy'means n. 'rnisis-alsoeontrcile by'valv drilling: with a rotary dill mg srig 1 Known ne artgpart'of the totl we 11 drill rem i' 'i' ied by' the smiling" so -that only porno of the total weight' df the drill stem rests on the uriii bit. vIii-"ther01lowin description "where the-weisht -"carfied on the drill bit is mentioned, it will beundersteod tna-t-a decrease the weight carried (m-"the d bit 471 16 is necessarily accompanied byan increase in weight supported by 't'heurfl-nng line and vice In -th" use of the apparatus described/the weigntincieatoro is-adiusteu so that'wnenl-a redetermined range of weight is" carried by the drilling -hit, slide M has ahormal ositien between resistances H and I3 so thati t mah'es'no coiitact'wi-t'h'ei ther dftl iesresistances as long as the weight on thebit stays within said predetermined range. this selected range the valve member of vaive'F is in its 'i'iormal position with groove 4e between ports 44 and 45. vIf the weight-carried by the drill-bit decreases, the-slide ['4 of potentiometer A-moves from-its normal position to activate motor]; in an amount sufficient to bring ringed "of valve member '42 adiacent'port 45. (The electrical connection of the potentiometer A. with two-phase motor D to accomplish this result will be apparent to a workman skilled in the art.) In this position air exhausts from the assemblies L and J to cause toothed wheel M to be moved counterclockwise, thus opening needle valve 16 to cause an increased flow of fluid through assembly III which allows a faster feed-off and should tend to increase the weight on the bit to bring it back to normal. If the correction brought about by exhausting air from port 45 through valve F is not sufiicient the weight on the bit will continue to decrease until it reaches such a value that the weight indicator with electrical connections including motor D will change the setting of valve F to bring ring 49 of valve member 42 adjacent port 4 6; when this occurs air exhausts through line 84 and causes valve (which for convenience in describing the results of its activation is called quick application valve) to open, allowing hydraulic fiuid to flow through line 82. Valve 15 will remain at this setting until the weight on the bit increases to such an amount that the controls move valve member 42 to the left, taking ring 49 out of contact with port 46 whereupon quick application valve 75 closes.

In the operation of the device described, if the weight on the bit increases beyond the predetermined normal range, the movement of slide l4 of potentiometer A in conjunction with twophase motor D will cause valve member 42 to move to the left to bring ring 49 adjacent port 44. When this occurs air can bleed out from assemblies H and K through lines 15 and I ll which, in turn, will cause assembly H to move swan toothed wheelz zfifiz in the clockwise direction clos i-rrg'needle valve 16 which willireduce theeimount of liquid i flowing through the 1 hydraulic system. AsIlong -Ias the Weightorithdbit is such that line H l 1 exhausts through valve-1F, assembly 1H moves toothed wheel v94 ar'cuately -at intervals progressively closing needle valve "76-. However, ii- :tl'reweight on 1 the hit increases still more, the potentiometer assembly A and -two+phase motor D will force valve member 4 2 still further to the left so that ring $9 adjacent to port t3 when this occurs valve 'M (whichfifor .convenien'ce' in describing athe resultsof its activation on' t-he drillingsystem isoalledthe drill off valve) is exhausted through line i 83 closingthis valve and which, turn, stops 1 fluid circulation through assembly H1 (since valve "i5 is normally closed) and dril leoif valve M- Will remain closed aszlong as thewveight on the bit is excessive which,:in turn, will cause member 42': to remain in its cen-- tral- *leftehan'd position. Whenthe weight on the bitiis decreased :to a predetermined value, the memher' tt willhemoved to the right so that line :83 'oan nolonger exhaust through port/-43, thus opening valve' lt and allowing fluidto pass ohce 'more'through the hydraulic system and'be controlled by the needle valve l 6.

- While I havedisclosed this specific embodiment of thepresentinvention, itwill be obvious toe-workman skilled in :thenart that various changes I in the vsizes, shapes and arrangements ofrthe-parts may be made without departing fro'm the scope of thepresent invention. I

Having iully described and illustrated a preferred -embodiment'of the present invention, what I desire to claim is:

1.' A- control system forcontrolling the -.speed of rotation of the 'drawworksof a rotary drilling rig having a weight indicatorcapable' of producing signals varying in response to changes in the weight carried by the drill bit and having a hydraulic system for altering the weight carried by the drill bit comprising, in combination, a pump mechanically connected to the drawworks for pumping hydraulic fluid upon rotation of the drawworks, a hydraulic circuit connecting an outlet of said pump with an inlet thereof, said hydraulic circuit having a manifold which includes a first by-pass line controlled by an airactuated first normally closed valve and a second by-pass line controlled by an air-actuated second normally open valve and by a needle valve, an air motor assembly mechanically connected to the needle valve having a first exhaust outlet and a second exhaust outlet and arranged to rotate the valve element of said needle valve in a clockwise direction when the first exhaust outlet is connected to the atmosphere and in a counterclockwise direction when the second exhaust outlet is connected to the atmosphere, an exhaust valve consisting of a body having four ports and a valve element movable in the valve body arranged to assume a first position connecting the first port to the atmosphere, a second position connecting the second port to the atmosphere, a third position connecting the third port to the atmosphere, a fourth position connecting the fourth port to the atmosphere and a fifth position in which flow of air through all of said ports is prevented, an air line connecting said second port of the exhaust valve to said first exhaust outlet of the air motor assembly, an air line connecting said third port of the exhaust valve to said second exhaust outlet of the air motor assembly, an air line connecting the actuating assembly of said second normally open valve to the first port of said exhaust valve, an air line connecting the actuating assembly of said first normally closed valve to said fourth port of said exhaust valve, and electrical control means actuated by the weight indicator arranged to move the valve element to a selected one of said five positions in response to signals received from said weight indicator.

2. A control system for controlling the speed of rotation of the drawworks of a rotary drilling rig having a weight indicator capable of producing signals varying in response to the changes in the Weight carried by the drill bit and having a hydraulic system for altering the weight carried by the drill bit comprising, in combination, a pump mechanically connected to the drawworks for pumping hydraulic fluid upon rotation of the drawworks, a hydraulic circuit connecting an outlet of said pump with an inlet thereof, said hydraulic circuit having a manifold which includes a first by-pass line controlled by an air-actuated first normally closed valve and a second by-pass line controlled by an airactuated second normally open valve and by a needle valve, an air motor assembly mechanically connected to the needle valve having a first exhaust outlet and a second exhaust outlet and arranged to rotate the valve element of said needle valve in a clockwise direction when the first exhaust outlet is connected to the atmosphere and in a counterclockwise direction when the second exhaust outlet is connected to the atmosphere, an exhaust valve consisting of a valve body having four serially arranged ports,

and a valve element movable in the valve body arranged to assume a first position connecting the first port to the atmosphere, a second position connecting a second port to the atmosphere,

a third position connecting the third port to the atmosphere, a fourth position connecting the fourth port to the atmosphere and a fifth position between the second and third positions in which the flow of air through all of said ports is prevented, an air line connecting said second port of the exhaust valve to the first exhaust outlet of the air motor assembly, an air line connecting said third port of the exhaust valve to the second exhaust outlet of the air motor assembly, an air line connecting the actuating assembly of said second normally open valve to the first port of said exhaust valve, an air line connecting the actuating assembly of said first normally closed valve to said fourth port of said exhaust valve, and electrical control means actuated by the weight indicator arranged to move the valve element to a selected one of said five positions in response to signals received from said weight indicator.

3. 'A device in accordance with claim 2 in which said weight indicator has a rotating pointer shaft and in which the electrically controlled means for moving the valve arrangement includes a rheostat with its slide mechanically connected to the shaft of said weight indicator, and electrically connected With a two-phase motor mechanically linked to the valve element of said exhaust valve.

ROBERT R. CROOKSTON.

References Cited in the file of this patent UNITED STATES PATENTS Crookston Nov. 29, 1949 

